The overall goal is to compare the efficacy of two intervention approaches to dietary change among patients with the metabolic syndrome. Metabolic syndrome, which affects nearly 27% of US adults, is a national priority for prevention of CHD as described by the National Cholesterol Education Program's Adult Treatment Panel III. Weight loss is paramount in recommendations for metabolic syndrome. Results from three recent review articles agreed that adding dietary fiber can aid weight loss and weight loss maintenance; dietary fiber also exerts clinical benefits on several components of the metabolic syndrome, including waist circumference, glucose and lipid homeostasis, and insulin control. Despite this, the average fiber intake of adults in the United States is less than half recommended levels. In addition, interventions that target dietary change have typically not been successful with adherence to all recommendations in the short term, and with maintaining changes in diet over the longer term. A contributing factor to poor dietary adherence is likely of the complexity of dietary guidelines. We propose that a simplified dietary intervention strategy that focuses on a key aspect of dietary quality, fiber intake, will overcome the poor adherence typically associated with dietary interventions and improve overall diet quality. We will recruit 240 overweight and obese adults from a primary care setting who meet diagnostic criteria for metabolic syndrome. The efficacy of the two dietary change interventions will be compared in a randomized controlled trial, with 120 patients per group. The two approaches are 1) the American Heart Association (AHA) Dietary Guidelines; and 2) a simple dietary change condition that focuses on increasing fiber. Patients in both conditions will receive intensive dietary instruction for 3 months, followed by a 9 month maintenance phase. Both conditions will receive dietary instructions via individual and group sessions led by registered dietitians. Assessments, including diet, anthropometrics, blood pressure, fasting blood glucose, glycosylated hemoglobin (HbA1c), blood lipids, insulin, inflammatory markers, medication use, depression, quality of life, and physical activity will be conducted at baseline and at 6-, and 12-months after randomization. A 3-month post-intensive intervention assessment will measure short-term changes in body weight, diet, and metabolic syndrome indicators. We hypothesize that participants randomized to the higher fiber condition will have significantly greater weight loss, improvements in metabolic health, and dietary quality at follow-up, compared to those randomized to the AHA diet condition. Such a simple message, if found efficacious for weight loss, metabolic health, dietary quality and adherence in a clinical setting might then be ideal for testing as a public health message. PUBLIC HEALTH RELEVANCE: Identifying a simple dietary recommendation for weight loss and metabolic health may demonstrate potential for a simple public health message to impact CHD prevention and metabolic syndrome. In a randomized clinical trial, we propose to compare the efficacy of two intervention approaches to dietary change for CHD prevention among persons with metabolic syndrome. The two approaches are 1) the AHA Dietary Guidelines; and 2) a simple dietary change condition that focuses on increasing fiber. We hypothesize that a message promoting high fiber intake may be the simple message that has potential to produce broad impact.